A dual-mode transceiver, which may be a mobile station, may support and switch between two different types of wireless communications systems. When a mobile station travels outside the boundary of the communications system with which it is currently communicating, it may be desirable to maintain the communication link by transferring the call to a neighboring system, if one exists. The current and neighboring communications systems may use any wireless technology, for example, Code Division Multiple Access (CDMA), which is a type of spread spectrum communications protocol, Advanced Mobile Phone Service (AMPS), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), or Global System for Mobile communication (GSM). If the neighboring system uses CDMA on the same frequency band as the current system, a soft handoff may be performed, that is, the handoff is performed without first breaking the link with the first system.
However, if the mobile station is traveling from a region serviced by a CDMA system to a region serviced by a system employing a different communications protocol, such as AMPS, or vice versa, then a soft handoff cannot be performed. In such a case, the communication link may be transferred through a hard handoff, wherein the current connection is broken before a new one is made. In the example of a hard handoff from AMPS to CDMA, this requires breaking the link to AMPS, going to another frequency, searching for pseudorandom noise (PN) code signals, returning to the original frequency and reestablishing the link. In general, prior art real-time processing techniques are impractical, if not totally unsuitable, for such a hard handoff. Due to the time-consuming and power-consuming calculations that are part of the processing, reestablishment of the link to AMPS is either detrimentally impaired or altogether impossible, and a dual mode hard handoff cannot be effected between AMPS and CDMA.